Interventions for Improving Coverage of Childhood Immunisation in Low- and Middle-Income Countries [2023 Update]

"Making well-informed decisions about how best to achieve and sustain high and equitable immunisation coverage in these countries will depend partly on decision-makers accessing the best scientific evidence about what interventions work, and integrating this evidence into their national health systems..."

It is estimated that 1.5 million children die each year from diseases preventable by vaccines currently recommended by the World Health Organization (WHO). There are varied reasons for failing to achieve universal coverage in different settings, such as public perceptions and political instability. Evidence is required to inform strategies to reach partially vaccinated and unvaccinated people in these countries. Such strategies also need to be tailored to local issues, needs, and conditions. The aim of this Cochrane Review was to evaluate the effect of different strategies to increase the number of children in low- and middle-income countries (LMICs) who are vaccinated to prevent infection by a disease. It is a second update of the Cochrane Review first published in 2011 and updated in 2016. (See Related Summaries, below.)

The review authors searched for studies that were published up to July 2022. They searched CENTRAL, MEDLINE, CINAHL, and Global Index Medicus (July 11 2022), as well as Embase, LILACS, and Sociological Abstracts (September 2 2014) and WHO ICTRP and ClinicalTrials.gov (July 11 2022). In addition, they screened reference lists of relevant systematic reviews for potentially eligible studies and carried out a citation search for 14 of the included studies (February 19 2020). Eligible studies involved interventions in LMICs that sought to reach caregivers of children under five years of age (parents/guardians), care providers, the community, the health system, or a combination of any of these. 

Forty‐one studies involving 100,747 participants are included in the review. Twenty studies were cluster‐randomised and 15 studies were individually randomised controlled trials (RCTs). Six studies were quasi‐randomised. The studies were conducted in 4 upper‐middle‐income countries (China, Georgia, Mexico, Guatemala), 11 lower‐middle‐income countries (Côte d'Ivoire, Ghana, Honduras, India, Indonesia, Kenya, Nigeria, Nepal, Nicaragua, Pakistan, Zimbabwe), and 3 lower‐income countries (Afghanistan, Mali, Rwanda).

The review team judged 9 of the included studies to have low risk of bias; the risk of bias in 8 studies was unclear, and 24 studies had high risk of bias.

The interventions evaluated in the studies were patient reminders (13 studies), health education (7 studies), household incentives (3 studies), regular immunisation outreach sessions (2 studies), supportive supervision (2 studies), digital register (2 studies), payment for performance (2 studies), home visits (1 study), integration of immunisation services with intermittent preventive treatment of malaria (1 study), engagement of community leaders (1 study), training on interpersonal communication skills (1 study), and logistic support to health facilities (1 study).

The review compared people receiving these strategies to people who only received the usual healthcare services. In brief, the studies showed the following:

• Immunisation outreach alone or in combination with non-monetary incentives or health education probably improves full vaccination uptake among children under 5 years of age.
• Health education may lead to more children receiving three doses of diphtheria-tetanus-pertussis containing vaccine (DTP3).
• The use of specially designed immunisation cards may improve the uptake of DTP3.
• Using phone call or text messages to remind caregivers about vaccination may have little or no effect on improving uptake of DTP3.
• Involvement of community leaders in combination with health provider intervention probably improves uptake of DTP3.
• It is unclear if training of health providers on interpersonal communication skills improves the uptake of DTP3.

In more detail:

• Use of community leaders in combination with provider intervention probably increases the uptake of DTP3/Penta 3 vaccine (risk ratio (RR) 1.37, 95% confidence interval (CI) 1.11 to 1.69; 1 study, 2,020 participants; moderate‐certainty evidence).
• The review found low‐certainty evidence that health education (RR 1.36, 95% CI 1.15 to 1.62; 6 studies, 4,375 participants) and home‐based records (RR 1.36, 95% CI 1.06 to 1.75; 3 studies, 4,019 participants) may improve coverage with DTP3/Penta 3 vaccine.
• The integration of immunisation with other services may improve full vaccination (RR 1.29, 95% CI 1.16 to 1.44; 1 study, 1,700 participants; low‐certainty evidence).
• Phone calls/short messages may have little or no effect on DTP3/Penta 3 vaccine uptake (RR 1.12, 95% CI 1.00 to 1.25; 6 studies, 3,869 participants; low‐certainty evidence).
• Wearable reminders probably have little or no effect on DTP3/Penta 3 uptake (RR 1.02, 95% CI 0.97 to 1.07; 2 studies, 1,567 participants; moderate‐certainty evidence).
• The evidence is uncertain about the effect of immunisation outreach on DTP3/Penta 3 vaccine uptake in children under 2 years of age (RR 1.32, 95% CI 1.11 to 1.56; 1 study, 541 participants; very low‐certainty evidence).
• The evidence is also uncertain about the following interventions improving full vaccination of children under 2 years of age: training of health providers on interpersonal communication skills (RR 5.65, 95% CI 3.62 to 8.83; 1 study, 420 participants; very low‐certainty evidence) and home visits (RR 1.29, 95% CI 1.15 to 1.45; 1 study, 419 participants; very low‐certainty evidence). The same applies to the effect of training of health providers on interpersonal communication skills on the uptake of DTP3/Penta 3 by one year of age (very low‐certainty evidence).

The review team's confidence in the evidence for the interventions studied ranged from moderate to very low, implying that the results of further research could differ from the results of this review. The main reasons for reduced confidence in the evidence are that in some of the studies people were not randomly placed into different intervention groups. This means that differences between the groups could be due to differences between people rather than between the interventions. For some interventions, the results were very inconsistent across the different studies, and, for some, only one study was available, or the intervention had few people studied.

The review team concludes that health education, home-based records, a combination of involvement of community leaders with health provider intervention, and integration of immunisation services may improve vaccine uptake. More rigorous RCTs are required to generate high-certainty evidence to inform policy and practice.